Patents by Inventor Surjit S. Chadha

Surjit S. Chadha has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6090309
    Abstract: A phosphor composition selected from a range of phosphor compositions is provided for discharging spent electrons from a display screen of a luminescent display. The selected phosphor composition is a mixture of phosphor species, including a dielectric phosphor species capable of emitting visible green, blue or red light when subjected to excitation electrons at a relatively high voltage and a conductive phosphor species capable of emitting visible green, blue or red light when subjected to energized excitation electrons at a relatively low voltage. The display screen of the luminescent display is coated with the selected phosphor composition to form a cathodoluminescent layer on the screen. The cathodoluminescent layer is then selectively subjected to excitation electrons having a voltage within a predetermined broad range. The excitation electrons impart their energy to the phosphor composition causing it to emit visible green, blue or red light, thereby creating an image on the screen.
    Type: Grant
    Filed: June 8, 1998
    Date of Patent: July 18, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Surjit S. Chadha, Charles M. Watkins
  • Patent number: 6059936
    Abstract: Powder phosphors are activated while their particle size is limited in growth to approximately 1 micron or less. The powder phosphors are rapidly annealed with one of a number of methods, including rapid thermal annealing, laser annealing, microwave annealing, and RF annealing.
    Type: Grant
    Filed: October 8, 1997
    Date of Patent: May 9, 2000
    Assignee: Micron Technology, Inc.
    Inventors: David A. Cathey, Surjit S. Chadha, Charles M. Watkins
  • Patent number: 6057638
    Abstract: According to one aspect of the invention, a field emission display is provided comprising: an anode; a phosphor screen located on the anode; a cathode; an evacuated space between the anode and the cathode; an emitter located on the cathode opposite the phosphor; wherein the emitter comprises an electropositive element both in a body of the emitter and on a surface of the emitter. According to another aspect of the invention a process for manufacturing an FED is provided comprising the steps of: forming an emitter comprising an electropositive element in the body of the tip; positioning the emitter in opposing relation to a phosphor display screen; creating an evacuated space between the emitter tip and the phosphor display screen; and causing the electropositive element to migrate to the an emission surface of the emitter.
    Type: Grant
    Filed: June 26, 1998
    Date of Patent: May 2, 2000
    Assignee: Micron Technology, Inc.
    Inventors: David A. Cathey, Surjit S. Chadha, Behnam Moradi
  • Patent number: 6042746
    Abstract: A multi-stage process for preparing a phosphor product includes the stages of selecting precursors of a dopant and a host lattice as the phosphor starting materials, grinding the starting materials in an initial grinding stage for an initial grinding time period to produce an initial ground material having a smaller particle size distribution than the starting materials, firing the initial ground material in an initial firing stage at an initial firing temperature for an initial firing time period to produce an initial fired material, grinding the initial fired material in an intermediate grinding stage for an intermediate grinding time period to produce an intermediate ground material having a smaller particle size than the initial fired material, wherein the intermediate grinding time period is substantially less than the initial grinding time period, firing the intermediate ground material in an intermediate firing stage at an intermediate firing temperature for an intermediate firing time to produce an in
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: March 28, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Surjit S. Chadha, Charles M. Watkins
  • Patent number: 6027790
    Abstract: The present invention is directed to a novel etching process for a semiconductor material which inhibits corrosion of metal comprised of pretreating the material, preferably with a surfactant, and then exposing the material to a mixture comprising a buffered oxide etch.
    Type: Grant
    Filed: June 10, 1998
    Date of Patent: February 22, 2000
    Assignee: Micron Technology, Inc.
    Inventors: Robert T. Rasmussen, Surjit S. Chadha, David A. Cathey
  • Patent number: 6008577
    Abstract: A flat panel display includes a magnetic material for focusing electrons onto a faceplate or phosphors of each pixel on a screen. In one embodiment, a display screen includes a faceplate having a magnetic material (30) deposited thereon. In an alternate embodiment, a field emission display including a substrate (11) with a cathode conductor (12); electron emitting tips (13) disposed over the cathode conductor (12); an insulator (14) disposed around the electron emitting tips (13); a conductive gate (15) over the insulator (14); and a magnetic material layer (19) for focusing electrons emitted from the emitting tips (13).
    Type: Grant
    Filed: December 1, 1997
    Date of Patent: December 28, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Robert T. Rasmussen, Charles M. Watkins, Surjit S. Chadha
  • Patent number: 6004480
    Abstract: A continuous automated process is provided for manufacturing a phosphor product having controlled particle size characteristics and enhanced luminescent performance characteristics for use in a luminescent display. A precursor host lattice solution, a precursor dopant solution and reagent solution are initially selected as the starting materials for the phosphor product and are mixed together to produce a liquid starting material mixture. The mixture is conveyed to a microwave reactor and heated therein in a first heating stage by subjecting the mixture to microwaves at a predetermined frequency for a time sufficient to convert the starting material mixture to a precursor complex. The precursor complex is conveyed to a fluidized bed reactor and heated therein in a second heating stage by a hot fluidizing gas for a time and at a temperature sufficient to convert the precursor complex to the phosphor product in particulate form.
    Type: Grant
    Filed: November 4, 1996
    Date of Patent: December 21, 1999
    Assignee: Micron Technology, Inc.
    Inventor: Surjit S. Chadha
  • Patent number: 5906771
    Abstract: A process is provided for manufacturing high-purity phosphors having utility in field emission displays. The high-purity phosphor is a host lattice infiltrated by a dopant that activates luminescent properties therein. The lattice and dopant are initially milled together to reduce their average particle size while simultaneously achieving complete mixing between the lattice and the dopant. The resulting mixture is maintained free of a flux or substantially any other treatment agent capable of contaminating the phosphor and placed in a heating vessel formed from a substantially impervious contaminant-free material. The mixture is heated to a high temperature effectuating thorough infiltration of the dopant into the lattice structure. The use of an impervious contaminant-free heating vessel and the exclusion of flux or other treatment agents from the mixture avoids undesirable contamination and undue particle size growth of the phosphor product during the manufacture thereof.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: May 25, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Charles M. Watkins, Surjit S. Chadha
  • Patent number: 5885477
    Abstract: The present invention is directed to a novel etching process for a semiconductor material which inhibits corrosion of metal comprised of pretreating the material, preferably with a surfactant, and then exposing the material to a mixture comprising salt, a buffered oxide etch, and optionally a surfactant.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: March 23, 1999
    Assignee: Micron Display Technology, Inc.
    Inventors: Robert T. Rasmussen, Surjit S. Chadha, David A. Cathey
  • Patent number: 5886461
    Abstract: The present invention is directed to a conductor/electrode for a faceplate anode of a field emission display wherein said conductor/electrode is comprised of tin oxide. Alternatively, the present invention is directed to a transparent conductor/electrode for a faceplate anode of a field emission display wherein said conductor/electrode is comprised of from about 90% to about 99% tin oxide and from about 1% to about 10% antimony.
    Type: Grant
    Filed: October 24, 1995
    Date of Patent: March 23, 1999
    Assignee: Micron Display Technology, Inc.
    Inventor: Surjit S. Chadha
  • Patent number: 5801103
    Abstract: The present invention is directed to a novel etching process for a semiconductor material which inhibits corrosion of metal comprised of pretreating the material, preferably with a surfactant, and then exposing the material to a mixture comprising a buffered oxide etch.
    Type: Grant
    Filed: December 4, 1995
    Date of Patent: September 1, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Robert T. Rasmussen, Surjit S. Chadha, David A. Cathey
  • Patent number: 5795206
    Abstract: A process is provided for forming spacers useful in large area displays. The process comprises steps of: forming bundles or boules comprising fiber strands which are held together with a binder; slicing the bundles or boules into slices; adhering the slices on an electrode plate of the display; and removing the binder. In the step of forming bundles or boules comprising fiber strands, the function of the binder is initially or fully performed by glass tubings surrounding the glass fibers. The clad glass of the envelopes etches more readily than the core glass.
    Type: Grant
    Filed: September 15, 1995
    Date of Patent: August 18, 1998
    Assignee: Micron Technology, Inc.
    Inventors: David A. Cathey, Charles M. Watkins, Darryl M. Stansbury, James J. Hofmann, Robert T. Rasmussen, Surjit S. Chadha
  • Patent number: 5788881
    Abstract: A phosphor composition selected from a range of phosphor compositions is provided for discharging spent electrons from a display screen of a luminescent display. The selected phosphor composition is a mixture of phosphor species, including a dielectric phosphor species capable of emitting visible green, blue or red light when subjected to excitation electrons at a relatively high voltage and a conductive phosphor species capable of emitting visible green, blue or red light when subjected to energized excitation electrons at a relatively low voltage. The display screen of the luminescent display is coated with the selected phosphor composition to form a cathodoluminescent layer on the screen. The cathodoluminescent layer is then selectively subjected to excitation electrons having a voltage within a predetermined broad range. The excitation electrons impart their energy to the phosphor composition causing it to emit visible green, blue or red light, thereby creating an image on the screen.
    Type: Grant
    Filed: October 25, 1995
    Date of Patent: August 4, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Surjit S. Chadha, Charles M. Watkins
  • Patent number: 5779920
    Abstract: The present invention provides luminescent screens with a mask layer, methods of manufacturing the screens, and display devices incorporating the screens. The mask layer is attached to a matrix defining the pixels in the screen and preferably includes voids formed therethrough corresponding to each pixel. The voids in the mask layer preferably have a size generally corresponding to that of the pixels near the phosphor material and narrow in the direction of the electron source.
    Type: Grant
    Filed: November 12, 1996
    Date of Patent: July 14, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Surjit S. Chadha, Dean A. Wilkinson
  • Patent number: 5776540
    Abstract: A process for manufacturing a conductive and light-absorbing baseplate for use in a field emission display is disclosed. A surface of the baseplate is coated with a praseodymium oxide- and manganese oxide-containing layer having a resistivity that does not exceed 1.times.10.sup.5 .OMEGA.-cm. The coating may be placed on the baseplate by radiofrequency sputtering, laser ablation, plasma deposition or the like. Suitable praseodymium sources include praseodymium acetate, praseodymium oxalate and Pr(THd).sub.3, while suitable manganese sources include MnO.sub.2 and MnCO.sub.3.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: July 7, 1998
    Assignee: Micron Display Technology, Inc.
    Inventors: Surjit S. Chadha, Robert T. Rasmussen
  • Patent number: 5772488
    Abstract: According to one aspect of the invention, a field emission display is provided comprising: an anode; a phosphor screen located on the anode; a cathode; an evacuated space between the anode and the cathode; an emitter located on the cathode opposite the phosphor; wherein the emitter comprises an electropositive element both in a body of the emitter and on a surface of the emitter. According to another aspect of the invention a process for manufacturing an FED is provided comprising the steps of: forming an emitter comprising an electropositive element in the body of the tip; positioning the emitter in opposing relation to a phosphor display screen; creating an evacuated space between the emitter tip and the phosphor display screen; and causing the electropositive element to migrate to the an emission surface of the emitter.
    Type: Grant
    Filed: October 16, 1995
    Date of Patent: June 30, 1998
    Assignee: Micron Display Technology, Inc.
    Inventors: David A. Cathey, Surjit S. Chadha, Behnam Moradi
  • Patent number: 5759446
    Abstract: A conductive, light-absorbing baseplate for use in a field emission display is disclosed. The interior surface of the baseplate is coated with a praseodymium-manganese oxide layer having a resistivity that does not exceed 1.times.10.sup.5 .OMEGA..multidot.cm. A field emission display is also disclosed which comprises the conductive, light-absorbing baseplate, as well as processes for manufacturing the baseplate, field emission display and the conductive, light-absorbing praseodymium-manganese oxide material used to coat the baseplate.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: June 2, 1998
    Assignee: Micron Display Technology, Inc.
    Inventors: Surjit S. Chadha, Robert T. Rasmussen
  • Patent number: 5744907
    Abstract: Binders, both inorganic and organic, are used for providing sufficient binding action to hold powder phosphor particles together as well as to the glass screen of a field emission display device.
    Type: Grant
    Filed: January 19, 1996
    Date of Patent: April 28, 1998
    Assignee: Micron Display Technology, Inc.
    Inventors: Surjit S. Chadha, Charles M. Watkins
  • Patent number: 5695661
    Abstract: The present invention is directed to a novel etching process for a semiconductor material which inhibits corrosion of metal comprised of pretreating the material, preferably with a surfactant, and then exposing the material to a mixture comprising salt, a buffered oxide etch, and optionally a surfactant.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 9, 1997
    Assignee: Micron Display Technology, Inc.
    Inventors: Robert T. Rasmussen, Surjit S. Chadha, David A. Cathey
  • Patent number: 5695809
    Abstract: A method of manufacturing phosphor screens is disclosed. The method uses "sol-gel" for disposing a thin film of phosphor on a transparent substrate. The thin film of phosphor is applied in continuous form or in the form of an accurate dot pattern. The rastering of said dot pattern is performed either by screen printing before annealing the sol-gel, or by selective laser curing of a continuous thin film and washing off the non-cured portions. The phosphor screens are useful as monochrome or as full-color faceplates of field emission displays or cathode ray tubes.
    Type: Grant
    Filed: November 14, 1995
    Date of Patent: December 9, 1997
    Assignee: Micron Display Technology, Inc.
    Inventors: Surjit S. Chadha, James J. Alwan